Plant RuBisCo assembly in E. coli with five chloroplast chaperones including BSD2

• Published in: Science (American Association for the Advancement of Science) 2017-12, Vol.358 (6368), p.1272-1278
• Main Authors: Aigner, H., Wilson, R. H., Bracher, A., Calisse, L., Bhat, J. Y., Hartl, F. U., Hayer-Hartl, M.
• Format: Article
• Language: English
• Subjects: Agricultural production; Arabidopsis - enzymology; Arabidopsis Proteins - chemistry; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Assembly; Bacteria; Carbon dioxide; Carbon dioxide fixation; Carbon sequestration; Catalysis; Chaperones; Chaperonin 60 - chemistry; Chaperonin 60 - genetics; Chaperonin 60 - metabolism; Chaperonins; Chloroplasts; Chloroplasts - metabolism; Crop yield; Crops; Crystallography, X-Ray; E coli; Enzymes; Escherichia coli; Escherichia coli - enzymology; Functional analysis; Group I Chaperonins - chemistry; Group I Chaperonins - genetics; Group I Chaperonins - metabolism; Host plants; Molecular Chaperones - chemistry; Molecular Chaperones - genetics; Molecular Chaperones - metabolism; Motivation; Mutagenesis; Photorespiration; Photosynthesis; Plants (botany); Protein Folding; Recombinant Proteins - chemistry; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; Ribulose-bisphosphate carboxylase; Ribulose-Bisphosphate Carboxylase - chemistry; Ribulose-Bisphosphate Carboxylase - genetics; Ribulose-Bisphosphate Carboxylase - metabolism; Structure-function relationships
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.aap9221

Plant RuBisCo, a complex of eight large and eight small subunits, catalyzes the fixation of CO₂ in photosynthesis. The low catalytic efficiency of RuBisCo provides strong motivation to reengineer the enzyme with the goal of increasing crop yields. However, genetic manipulation has been hampered by the failure to express plant RuBisCo in a bacterial host. We achieved the functional expression of Arabidopsis thaliana RuBisCo in Escherichia coli by coexpressing multiple chloroplast chaperones. These include the chaperonins Cpn60/Cpn20, RuBisCo accumulation factors 1 and 2, RbcX, and bundle-sheath defective-2 (BSD2). Our structural and functional analysis revealed the role of BSD2 in stabilizing an end-state assembly intermediate of eight RuBisCo large subunits until the small subunits become available. The ability to produce plant RuBisCo recombinantly will facilitate efforts to improve the enzyme through mutagenesis.